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1/*
2 * net/sched/sch_tbf.c Token Bucket Filter queue.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * Dmitry Torokhov <dtor@mail.ru> - allow attaching inner qdiscs -
11 * original idea by Martin Devera
12 *
13 */
14
15#include <linux/module.h>
16#include <linux/types.h>
17#include <linux/kernel.h>
18#include <linux/string.h>
19#include <linux/errno.h>
20#include <linux/skbuff.h>
21#include <net/netlink.h>
22#include <net/sch_generic.h>
23#include <net/pkt_sched.h>
24
25
26/* Simple Token Bucket Filter.
27 =======================================
28
29 SOURCE.
30 -------
31
32 None.
33
34 Description.
35 ------------
36
37 A data flow obeys TBF with rate R and depth B, if for any
38 time interval t_i...t_f the number of transmitted bits
39 does not exceed B + R*(t_f-t_i).
40
41 Packetized version of this definition:
42 The sequence of packets of sizes s_i served at moments t_i
43 obeys TBF, if for any i<=k:
44
45 s_i+....+s_k <= B + R*(t_k - t_i)
46
47 Algorithm.
48 ----------
49
50 Let N(t_i) be B/R initially and N(t) grow continuously with time as:
51
52 N(t+delta) = min{B/R, N(t) + delta}
53
54 If the first packet in queue has length S, it may be
55 transmitted only at the time t_* when S/R <= N(t_*),
56 and in this case N(t) jumps:
57
58 N(t_* + 0) = N(t_* - 0) - S/R.
59
60
61
62 Actually, QoS requires two TBF to be applied to a data stream.
63 One of them controls steady state burst size, another
64 one with rate P (peak rate) and depth M (equal to link MTU)
65 limits bursts at a smaller time scale.
66
67 It is easy to see that P>R, and B>M. If P is infinity, this double
68 TBF is equivalent to a single one.
69
70 When TBF works in reshaping mode, latency is estimated as:
71
72 lat = max ((L-B)/R, (L-M)/P)
73
74
75 NOTES.
76 ------
77
78 If TBF throttles, it starts a watchdog timer, which will wake it up
79 when it is ready to transmit.
80 Note that the minimal timer resolution is 1/HZ.
81 If no new packets arrive during this period,
82 or if the device is not awaken by EOI for some previous packet,
83 TBF can stop its activity for 1/HZ.
84
85
86 This means, that with depth B, the maximal rate is
87
88 R_crit = B*HZ
89
90 F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes.
91
92 Note that the peak rate TBF is much more tough: with MTU 1500
93 P_crit = 150Kbytes/sec. So, if you need greater peak
94 rates, use alpha with HZ=1000 :-)
95
96 With classful TBF, limit is just kept for backwards compatibility.
97 It is passed to the default bfifo qdisc - if the inner qdisc is
98 changed the limit is not effective anymore.
99*/
100
101struct tbf_sched_data {
102/* Parameters */
103 u32 limit; /* Maximal length of backlog: bytes */
104 u32 max_size;
105 s64 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */
106 s64 mtu;
107 struct psched_ratecfg rate;
108 struct psched_ratecfg peak;
109
110/* Variables */
111 s64 tokens; /* Current number of B tokens */
112 s64 ptokens; /* Current number of P tokens */
113 s64 t_c; /* Time check-point */
114 struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */
115 struct qdisc_watchdog watchdog; /* Watchdog timer */
116};
117
118
119/* Time to Length, convert time in ns to length in bytes
120 * to determinate how many bytes can be sent in given time.
121 */
122static u64 psched_ns_t2l(const struct psched_ratecfg *r,
123 u64 time_in_ns)
124{
125 /* The formula is :
126 * len = (time_in_ns * r->rate_bytes_ps) / NSEC_PER_SEC
127 */
128 u64 len = time_in_ns * r->rate_bytes_ps;
129
130 do_div(len, NSEC_PER_SEC);
131
132 if (unlikely(r->linklayer == TC_LINKLAYER_ATM)) {
133 do_div(len, 53);
134 len = len * 48;
135 }
136
137 if (len > r->overhead)
138 len -= r->overhead;
139 else
140 len = 0;
141
142 return len;
143}
144
145/*
146 * Return length of individual segments of a gso packet,
147 * including all headers (MAC, IP, TCP/UDP)
148 */
149static unsigned int skb_gso_mac_seglen(const struct sk_buff *skb)
150{
151 unsigned int hdr_len = skb_transport_header(skb) - skb_mac_header(skb);
152 return hdr_len + skb_gso_transport_seglen(skb);
153}
154
155/* GSO packet is too big, segment it so that tbf can transmit
156 * each segment in time
157 */
158static int tbf_segment(struct sk_buff *skb, struct Qdisc *sch)
159{
160 struct tbf_sched_data *q = qdisc_priv(sch);
161 struct sk_buff *segs, *nskb;
162 netdev_features_t features = netif_skb_features(skb);
163 unsigned int len = 0, prev_len = qdisc_pkt_len(skb);
164 int ret, nb;
165
166 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
167
168 if (IS_ERR_OR_NULL(segs))
169 return qdisc_reshape_fail(skb, sch);
170
171 nb = 0;
172 while (segs) {
173 nskb = segs->next;
174 segs->next = NULL;
175 qdisc_skb_cb(segs)->pkt_len = segs->len;
176 len += segs->len;
177 ret = qdisc_enqueue(segs, q->qdisc);
178 if (ret != NET_XMIT_SUCCESS) {
179 if (net_xmit_drop_count(ret))
180 qdisc_qstats_drop(sch);
181 } else {
182 nb++;
183 }
184 segs = nskb;
185 }
186 sch->q.qlen += nb;
187 if (nb > 1)
188 qdisc_tree_reduce_backlog(sch, 1 - nb, prev_len - len);
189 consume_skb(skb);
190 return nb > 0 ? NET_XMIT_SUCCESS : NET_XMIT_DROP;
191}
192
193static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
194{
195 struct tbf_sched_data *q = qdisc_priv(sch);
196 int ret;
197
198 if (qdisc_pkt_len(skb) > q->max_size) {
199 if (skb_is_gso(skb) && skb_gso_mac_seglen(skb) <= q->max_size)
200 return tbf_segment(skb, sch);
201 return qdisc_reshape_fail(skb, sch);
202 }
203 ret = qdisc_enqueue(skb, q->qdisc);
204 if (ret != NET_XMIT_SUCCESS) {
205 if (net_xmit_drop_count(ret))
206 qdisc_qstats_drop(sch);
207 return ret;
208 }
209
210 sch->q.qlen++;
211 return NET_XMIT_SUCCESS;
212}
213
214static unsigned int tbf_drop(struct Qdisc *sch)
215{
216 struct tbf_sched_data *q = qdisc_priv(sch);
217 unsigned int len = 0;
218
219 if (q->qdisc->ops->drop && (len = q->qdisc->ops->drop(q->qdisc)) != 0) {
220 sch->q.qlen--;
221 qdisc_qstats_drop(sch);
222 }
223 return len;
224}
225
226static bool tbf_peak_present(const struct tbf_sched_data *q)
227{
228 return q->peak.rate_bytes_ps;
229}
230
231static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
232{
233 struct tbf_sched_data *q = qdisc_priv(sch);
234 struct sk_buff *skb;
235
236 skb = q->qdisc->ops->peek(q->qdisc);
237
238 if (skb) {
239 s64 now;
240 s64 toks;
241 s64 ptoks = 0;
242 unsigned int len = qdisc_pkt_len(skb);
243
244 now = ktime_get_ns();
245 toks = min_t(s64, now - q->t_c, q->buffer);
246
247 if (tbf_peak_present(q)) {
248 ptoks = toks + q->ptokens;
249 if (ptoks > q->mtu)
250 ptoks = q->mtu;
251 ptoks -= (s64) psched_l2t_ns(&q->peak, len);
252 }
253 toks += q->tokens;
254 if (toks > q->buffer)
255 toks = q->buffer;
256 toks -= (s64) psched_l2t_ns(&q->rate, len);
257
258 if ((toks|ptoks) >= 0) {
259 skb = qdisc_dequeue_peeked(q->qdisc);
260 if (unlikely(!skb))
261 return NULL;
262
263 q->t_c = now;
264 q->tokens = toks;
265 q->ptokens = ptoks;
266 sch->q.qlen--;
267 qdisc_unthrottled(sch);
268 qdisc_bstats_update(sch, skb);
269 return skb;
270 }
271
272 qdisc_watchdog_schedule_ns(&q->watchdog,
273 now + max_t(long, -toks, -ptoks),
274 true);
275
276 /* Maybe we have a shorter packet in the queue,
277 which can be sent now. It sounds cool,
278 but, however, this is wrong in principle.
279 We MUST NOT reorder packets under these circumstances.
280
281 Really, if we split the flow into independent
282 subflows, it would be a very good solution.
283 This is the main idea of all FQ algorithms
284 (cf. CSZ, HPFQ, HFSC)
285 */
286
287 qdisc_qstats_overlimit(sch);
288 }
289 return NULL;
290}
291
292static void tbf_reset(struct Qdisc *sch)
293{
294 struct tbf_sched_data *q = qdisc_priv(sch);
295
296 qdisc_reset(q->qdisc);
297 sch->q.qlen = 0;
298 q->t_c = ktime_get_ns();
299 q->tokens = q->buffer;
300 q->ptokens = q->mtu;
301 qdisc_watchdog_cancel(&q->watchdog);
302}
303
304static const struct nla_policy tbf_policy[TCA_TBF_MAX + 1] = {
305 [TCA_TBF_PARMS] = { .len = sizeof(struct tc_tbf_qopt) },
306 [TCA_TBF_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
307 [TCA_TBF_PTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
308 [TCA_TBF_RATE64] = { .type = NLA_U64 },
309 [TCA_TBF_PRATE64] = { .type = NLA_U64 },
310 [TCA_TBF_BURST] = { .type = NLA_U32 },
311 [TCA_TBF_PBURST] = { .type = NLA_U32 },
312};
313
314static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
315{
316 int err;
317 struct tbf_sched_data *q = qdisc_priv(sch);
318 struct nlattr *tb[TCA_TBF_MAX + 1];
319 struct tc_tbf_qopt *qopt;
320 struct Qdisc *child = NULL;
321 struct psched_ratecfg rate;
322 struct psched_ratecfg peak;
323 u64 max_size;
324 s64 buffer, mtu;
325 u64 rate64 = 0, prate64 = 0;
326
327 err = nla_parse_nested(tb, TCA_TBF_MAX, opt, tbf_policy);
328 if (err < 0)
329 return err;
330
331 err = -EINVAL;
332 if (tb[TCA_TBF_PARMS] == NULL)
333 goto done;
334
335 qopt = nla_data(tb[TCA_TBF_PARMS]);
336 if (qopt->rate.linklayer == TC_LINKLAYER_UNAWARE)
337 qdisc_put_rtab(qdisc_get_rtab(&qopt->rate,
338 tb[TCA_TBF_RTAB]));
339
340 if (qopt->peakrate.linklayer == TC_LINKLAYER_UNAWARE)
341 qdisc_put_rtab(qdisc_get_rtab(&qopt->peakrate,
342 tb[TCA_TBF_PTAB]));
343
344 buffer = min_t(u64, PSCHED_TICKS2NS(qopt->buffer), ~0U);
345 mtu = min_t(u64, PSCHED_TICKS2NS(qopt->mtu), ~0U);
346
347 if (tb[TCA_TBF_RATE64])
348 rate64 = nla_get_u64(tb[TCA_TBF_RATE64]);
349 psched_ratecfg_precompute(&rate, &qopt->rate, rate64);
350
351 if (tb[TCA_TBF_BURST]) {
352 max_size = nla_get_u32(tb[TCA_TBF_BURST]);
353 buffer = psched_l2t_ns(&rate, max_size);
354 } else {
355 max_size = min_t(u64, psched_ns_t2l(&rate, buffer), ~0U);
356 }
357
358 if (qopt->peakrate.rate) {
359 if (tb[TCA_TBF_PRATE64])
360 prate64 = nla_get_u64(tb[TCA_TBF_PRATE64]);
361 psched_ratecfg_precompute(&peak, &qopt->peakrate, prate64);
362 if (peak.rate_bytes_ps <= rate.rate_bytes_ps) {
363 pr_warn_ratelimited("sch_tbf: peakrate %llu is lower than or equals to rate %llu !\n",
364 peak.rate_bytes_ps, rate.rate_bytes_ps);
365 err = -EINVAL;
366 goto done;
367 }
368
369 if (tb[TCA_TBF_PBURST]) {
370 u32 pburst = nla_get_u32(tb[TCA_TBF_PBURST]);
371 max_size = min_t(u32, max_size, pburst);
372 mtu = psched_l2t_ns(&peak, pburst);
373 } else {
374 max_size = min_t(u64, max_size, psched_ns_t2l(&peak, mtu));
375 }
376 } else {
377 memset(&peak, 0, sizeof(peak));
378 }
379
380 if (max_size < psched_mtu(qdisc_dev(sch)))
381 pr_warn_ratelimited("sch_tbf: burst %llu is lower than device %s mtu (%u) !\n",
382 max_size, qdisc_dev(sch)->name,
383 psched_mtu(qdisc_dev(sch)));
384
385 if (!max_size) {
386 err = -EINVAL;
387 goto done;
388 }
389
390 if (q->qdisc != &noop_qdisc) {
391 err = fifo_set_limit(q->qdisc, qopt->limit);
392 if (err)
393 goto done;
394 } else if (qopt->limit > 0) {
395 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit);
396 if (IS_ERR(child)) {
397 err = PTR_ERR(child);
398 goto done;
399 }
400 }
401
402 sch_tree_lock(sch);
403 if (child) {
404 qdisc_tree_reduce_backlog(q->qdisc, q->qdisc->q.qlen,
405 q->qdisc->qstats.backlog);
406 qdisc_destroy(q->qdisc);
407 q->qdisc = child;
408 }
409 q->limit = qopt->limit;
410 if (tb[TCA_TBF_PBURST])
411 q->mtu = mtu;
412 else
413 q->mtu = PSCHED_TICKS2NS(qopt->mtu);
414 q->max_size = max_size;
415 if (tb[TCA_TBF_BURST])
416 q->buffer = buffer;
417 else
418 q->buffer = PSCHED_TICKS2NS(qopt->buffer);
419 q->tokens = q->buffer;
420 q->ptokens = q->mtu;
421
422 memcpy(&q->rate, &rate, sizeof(struct psched_ratecfg));
423 memcpy(&q->peak, &peak, sizeof(struct psched_ratecfg));
424
425 sch_tree_unlock(sch);
426 err = 0;
427done:
428 return err;
429}
430
431static int tbf_init(struct Qdisc *sch, struct nlattr *opt)
432{
433 struct tbf_sched_data *q = qdisc_priv(sch);
434
435 if (opt == NULL)
436 return -EINVAL;
437
438 q->t_c = ktime_get_ns();
439 qdisc_watchdog_init(&q->watchdog, sch);
440 q->qdisc = &noop_qdisc;
441
442 return tbf_change(sch, opt);
443}
444
445static void tbf_destroy(struct Qdisc *sch)
446{
447 struct tbf_sched_data *q = qdisc_priv(sch);
448
449 qdisc_watchdog_cancel(&q->watchdog);
450 qdisc_destroy(q->qdisc);
451}
452
453static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
454{
455 struct tbf_sched_data *q = qdisc_priv(sch);
456 struct nlattr *nest;
457 struct tc_tbf_qopt opt;
458
459 sch->qstats.backlog = q->qdisc->qstats.backlog;
460 nest = nla_nest_start(skb, TCA_OPTIONS);
461 if (nest == NULL)
462 goto nla_put_failure;
463
464 opt.limit = q->limit;
465 psched_ratecfg_getrate(&opt.rate, &q->rate);
466 if (tbf_peak_present(q))
467 psched_ratecfg_getrate(&opt.peakrate, &q->peak);
468 else
469 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
470 opt.mtu = PSCHED_NS2TICKS(q->mtu);
471 opt.buffer = PSCHED_NS2TICKS(q->buffer);
472 if (nla_put(skb, TCA_TBF_PARMS, sizeof(opt), &opt))
473 goto nla_put_failure;
474 if (q->rate.rate_bytes_ps >= (1ULL << 32) &&
475 nla_put_u64(skb, TCA_TBF_RATE64, q->rate.rate_bytes_ps))
476 goto nla_put_failure;
477 if (tbf_peak_present(q) &&
478 q->peak.rate_bytes_ps >= (1ULL << 32) &&
479 nla_put_u64(skb, TCA_TBF_PRATE64, q->peak.rate_bytes_ps))
480 goto nla_put_failure;
481
482 return nla_nest_end(skb, nest);
483
484nla_put_failure:
485 nla_nest_cancel(skb, nest);
486 return -1;
487}
488
489static int tbf_dump_class(struct Qdisc *sch, unsigned long cl,
490 struct sk_buff *skb, struct tcmsg *tcm)
491{
492 struct tbf_sched_data *q = qdisc_priv(sch);
493
494 tcm->tcm_handle |= TC_H_MIN(1);
495 tcm->tcm_info = q->qdisc->handle;
496
497 return 0;
498}
499
500static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
501 struct Qdisc **old)
502{
503 struct tbf_sched_data *q = qdisc_priv(sch);
504
505 if (new == NULL)
506 new = &noop_qdisc;
507
508 *old = qdisc_replace(sch, new, &q->qdisc);
509 return 0;
510}
511
512static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg)
513{
514 struct tbf_sched_data *q = qdisc_priv(sch);
515 return q->qdisc;
516}
517
518static unsigned long tbf_get(struct Qdisc *sch, u32 classid)
519{
520 return 1;
521}
522
523static void tbf_put(struct Qdisc *sch, unsigned long arg)
524{
525}
526
527static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker)
528{
529 if (!walker->stop) {
530 if (walker->count >= walker->skip)
531 if (walker->fn(sch, 1, walker) < 0) {
532 walker->stop = 1;
533 return;
534 }
535 walker->count++;
536 }
537}
538
539static const struct Qdisc_class_ops tbf_class_ops = {
540 .graft = tbf_graft,
541 .leaf = tbf_leaf,
542 .get = tbf_get,
543 .put = tbf_put,
544 .walk = tbf_walk,
545 .dump = tbf_dump_class,
546};
547
548static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
549 .next = NULL,
550 .cl_ops = &tbf_class_ops,
551 .id = "tbf",
552 .priv_size = sizeof(struct tbf_sched_data),
553 .enqueue = tbf_enqueue,
554 .dequeue = tbf_dequeue,
555 .peek = qdisc_peek_dequeued,
556 .drop = tbf_drop,
557 .init = tbf_init,
558 .reset = tbf_reset,
559 .destroy = tbf_destroy,
560 .change = tbf_change,
561 .dump = tbf_dump,
562 .owner = THIS_MODULE,
563};
564
565static int __init tbf_module_init(void)
566{
567 return register_qdisc(&tbf_qdisc_ops);
568}
569
570static void __exit tbf_module_exit(void)
571{
572 unregister_qdisc(&tbf_qdisc_ops);
573}
574module_init(tbf_module_init)
575module_exit(tbf_module_exit)
576MODULE_LICENSE("GPL");
1/*
2 * net/sched/sch_tbf.c Token Bucket Filter queue.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * Dmitry Torokhov <dtor@mail.ru> - allow attaching inner qdiscs -
11 * original idea by Martin Devera
12 *
13 */
14
15#include <linux/module.h>
16#include <linux/types.h>
17#include <linux/kernel.h>
18#include <linux/string.h>
19#include <linux/errno.h>
20#include <linux/skbuff.h>
21#include <net/netlink.h>
22#include <net/pkt_sched.h>
23
24
25/* Simple Token Bucket Filter.
26 =======================================
27
28 SOURCE.
29 -------
30
31 None.
32
33 Description.
34 ------------
35
36 A data flow obeys TBF with rate R and depth B, if for any
37 time interval t_i...t_f the number of transmitted bits
38 does not exceed B + R*(t_f-t_i).
39
40 Packetized version of this definition:
41 The sequence of packets of sizes s_i served at moments t_i
42 obeys TBF, if for any i<=k:
43
44 s_i+....+s_k <= B + R*(t_k - t_i)
45
46 Algorithm.
47 ----------
48
49 Let N(t_i) be B/R initially and N(t) grow continuously with time as:
50
51 N(t+delta) = min{B/R, N(t) + delta}
52
53 If the first packet in queue has length S, it may be
54 transmitted only at the time t_* when S/R <= N(t_*),
55 and in this case N(t) jumps:
56
57 N(t_* + 0) = N(t_* - 0) - S/R.
58
59
60
61 Actually, QoS requires two TBF to be applied to a data stream.
62 One of them controls steady state burst size, another
63 one with rate P (peak rate) and depth M (equal to link MTU)
64 limits bursts at a smaller time scale.
65
66 It is easy to see that P>R, and B>M. If P is infinity, this double
67 TBF is equivalent to a single one.
68
69 When TBF works in reshaping mode, latency is estimated as:
70
71 lat = max ((L-B)/R, (L-M)/P)
72
73
74 NOTES.
75 ------
76
77 If TBF throttles, it starts a watchdog timer, which will wake it up
78 when it is ready to transmit.
79 Note that the minimal timer resolution is 1/HZ.
80 If no new packets arrive during this period,
81 or if the device is not awaken by EOI for some previous packet,
82 TBF can stop its activity for 1/HZ.
83
84
85 This means, that with depth B, the maximal rate is
86
87 R_crit = B*HZ
88
89 F.e. for 10Mbit ethernet and HZ=100 the minimal allowed B is ~10Kbytes.
90
91 Note that the peak rate TBF is much more tough: with MTU 1500
92 P_crit = 150Kbytes/sec. So, if you need greater peak
93 rates, use alpha with HZ=1000 :-)
94
95 With classful TBF, limit is just kept for backwards compatibility.
96 It is passed to the default bfifo qdisc - if the inner qdisc is
97 changed the limit is not effective anymore.
98*/
99
100struct tbf_sched_data {
101/* Parameters */
102 u32 limit; /* Maximal length of backlog: bytes */
103 u32 buffer; /* Token bucket depth/rate: MUST BE >= MTU/B */
104 u32 mtu;
105 u32 max_size;
106 struct qdisc_rate_table *R_tab;
107 struct qdisc_rate_table *P_tab;
108
109/* Variables */
110 long tokens; /* Current number of B tokens */
111 long ptokens; /* Current number of P tokens */
112 psched_time_t t_c; /* Time check-point */
113 struct Qdisc *qdisc; /* Inner qdisc, default - bfifo queue */
114 struct qdisc_watchdog watchdog; /* Watchdog timer */
115};
116
117#define L2T(q, L) qdisc_l2t((q)->R_tab, L)
118#define L2T_P(q, L) qdisc_l2t((q)->P_tab, L)
119
120static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
121{
122 struct tbf_sched_data *q = qdisc_priv(sch);
123 int ret;
124
125 if (qdisc_pkt_len(skb) > q->max_size)
126 return qdisc_reshape_fail(skb, sch);
127
128 ret = qdisc_enqueue(skb, q->qdisc);
129 if (ret != NET_XMIT_SUCCESS) {
130 if (net_xmit_drop_count(ret))
131 sch->qstats.drops++;
132 return ret;
133 }
134
135 sch->q.qlen++;
136 return NET_XMIT_SUCCESS;
137}
138
139static unsigned int tbf_drop(struct Qdisc *sch)
140{
141 struct tbf_sched_data *q = qdisc_priv(sch);
142 unsigned int len = 0;
143
144 if (q->qdisc->ops->drop && (len = q->qdisc->ops->drop(q->qdisc)) != 0) {
145 sch->q.qlen--;
146 sch->qstats.drops++;
147 }
148 return len;
149}
150
151static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
152{
153 struct tbf_sched_data *q = qdisc_priv(sch);
154 struct sk_buff *skb;
155
156 skb = q->qdisc->ops->peek(q->qdisc);
157
158 if (skb) {
159 psched_time_t now;
160 long toks;
161 long ptoks = 0;
162 unsigned int len = qdisc_pkt_len(skb);
163
164 now = psched_get_time();
165 toks = psched_tdiff_bounded(now, q->t_c, q->buffer);
166
167 if (q->P_tab) {
168 ptoks = toks + q->ptokens;
169 if (ptoks > (long)q->mtu)
170 ptoks = q->mtu;
171 ptoks -= L2T_P(q, len);
172 }
173 toks += q->tokens;
174 if (toks > (long)q->buffer)
175 toks = q->buffer;
176 toks -= L2T(q, len);
177
178 if ((toks|ptoks) >= 0) {
179 skb = qdisc_dequeue_peeked(q->qdisc);
180 if (unlikely(!skb))
181 return NULL;
182
183 q->t_c = now;
184 q->tokens = toks;
185 q->ptokens = ptoks;
186 sch->q.qlen--;
187 qdisc_unthrottled(sch);
188 qdisc_bstats_update(sch, skb);
189 return skb;
190 }
191
192 qdisc_watchdog_schedule(&q->watchdog,
193 now + max_t(long, -toks, -ptoks));
194
195 /* Maybe we have a shorter packet in the queue,
196 which can be sent now. It sounds cool,
197 but, however, this is wrong in principle.
198 We MUST NOT reorder packets under these circumstances.
199
200 Really, if we split the flow into independent
201 subflows, it would be a very good solution.
202 This is the main idea of all FQ algorithms
203 (cf. CSZ, HPFQ, HFSC)
204 */
205
206 sch->qstats.overlimits++;
207 }
208 return NULL;
209}
210
211static void tbf_reset(struct Qdisc *sch)
212{
213 struct tbf_sched_data *q = qdisc_priv(sch);
214
215 qdisc_reset(q->qdisc);
216 sch->q.qlen = 0;
217 q->t_c = psched_get_time();
218 q->tokens = q->buffer;
219 q->ptokens = q->mtu;
220 qdisc_watchdog_cancel(&q->watchdog);
221}
222
223static const struct nla_policy tbf_policy[TCA_TBF_MAX + 1] = {
224 [TCA_TBF_PARMS] = { .len = sizeof(struct tc_tbf_qopt) },
225 [TCA_TBF_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
226 [TCA_TBF_PTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
227};
228
229static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
230{
231 int err;
232 struct tbf_sched_data *q = qdisc_priv(sch);
233 struct nlattr *tb[TCA_TBF_PTAB + 1];
234 struct tc_tbf_qopt *qopt;
235 struct qdisc_rate_table *rtab = NULL;
236 struct qdisc_rate_table *ptab = NULL;
237 struct Qdisc *child = NULL;
238 int max_size, n;
239
240 err = nla_parse_nested(tb, TCA_TBF_PTAB, opt, tbf_policy);
241 if (err < 0)
242 return err;
243
244 err = -EINVAL;
245 if (tb[TCA_TBF_PARMS] == NULL)
246 goto done;
247
248 qopt = nla_data(tb[TCA_TBF_PARMS]);
249 rtab = qdisc_get_rtab(&qopt->rate, tb[TCA_TBF_RTAB]);
250 if (rtab == NULL)
251 goto done;
252
253 if (qopt->peakrate.rate) {
254 if (qopt->peakrate.rate > qopt->rate.rate)
255 ptab = qdisc_get_rtab(&qopt->peakrate, tb[TCA_TBF_PTAB]);
256 if (ptab == NULL)
257 goto done;
258 }
259
260 for (n = 0; n < 256; n++)
261 if (rtab->data[n] > qopt->buffer)
262 break;
263 max_size = (n << qopt->rate.cell_log) - 1;
264 if (ptab) {
265 int size;
266
267 for (n = 0; n < 256; n++)
268 if (ptab->data[n] > qopt->mtu)
269 break;
270 size = (n << qopt->peakrate.cell_log) - 1;
271 if (size < max_size)
272 max_size = size;
273 }
274 if (max_size < 0)
275 goto done;
276
277 if (q->qdisc != &noop_qdisc) {
278 err = fifo_set_limit(q->qdisc, qopt->limit);
279 if (err)
280 goto done;
281 } else if (qopt->limit > 0) {
282 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit);
283 if (IS_ERR(child)) {
284 err = PTR_ERR(child);
285 goto done;
286 }
287 }
288
289 sch_tree_lock(sch);
290 if (child) {
291 qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);
292 qdisc_destroy(q->qdisc);
293 q->qdisc = child;
294 }
295 q->limit = qopt->limit;
296 q->mtu = qopt->mtu;
297 q->max_size = max_size;
298 q->buffer = qopt->buffer;
299 q->tokens = q->buffer;
300 q->ptokens = q->mtu;
301
302 swap(q->R_tab, rtab);
303 swap(q->P_tab, ptab);
304
305 sch_tree_unlock(sch);
306 err = 0;
307done:
308 if (rtab)
309 qdisc_put_rtab(rtab);
310 if (ptab)
311 qdisc_put_rtab(ptab);
312 return err;
313}
314
315static int tbf_init(struct Qdisc *sch, struct nlattr *opt)
316{
317 struct tbf_sched_data *q = qdisc_priv(sch);
318
319 if (opt == NULL)
320 return -EINVAL;
321
322 q->t_c = psched_get_time();
323 qdisc_watchdog_init(&q->watchdog, sch);
324 q->qdisc = &noop_qdisc;
325
326 return tbf_change(sch, opt);
327}
328
329static void tbf_destroy(struct Qdisc *sch)
330{
331 struct tbf_sched_data *q = qdisc_priv(sch);
332
333 qdisc_watchdog_cancel(&q->watchdog);
334
335 if (q->P_tab)
336 qdisc_put_rtab(q->P_tab);
337 if (q->R_tab)
338 qdisc_put_rtab(q->R_tab);
339
340 qdisc_destroy(q->qdisc);
341}
342
343static int tbf_dump(struct Qdisc *sch, struct sk_buff *skb)
344{
345 struct tbf_sched_data *q = qdisc_priv(sch);
346 struct nlattr *nest;
347 struct tc_tbf_qopt opt;
348
349 nest = nla_nest_start(skb, TCA_OPTIONS);
350 if (nest == NULL)
351 goto nla_put_failure;
352
353 opt.limit = q->limit;
354 opt.rate = q->R_tab->rate;
355 if (q->P_tab)
356 opt.peakrate = q->P_tab->rate;
357 else
358 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
359 opt.mtu = q->mtu;
360 opt.buffer = q->buffer;
361 NLA_PUT(skb, TCA_TBF_PARMS, sizeof(opt), &opt);
362
363 nla_nest_end(skb, nest);
364 return skb->len;
365
366nla_put_failure:
367 nla_nest_cancel(skb, nest);
368 return -1;
369}
370
371static int tbf_dump_class(struct Qdisc *sch, unsigned long cl,
372 struct sk_buff *skb, struct tcmsg *tcm)
373{
374 struct tbf_sched_data *q = qdisc_priv(sch);
375
376 tcm->tcm_handle |= TC_H_MIN(1);
377 tcm->tcm_info = q->qdisc->handle;
378
379 return 0;
380}
381
382static int tbf_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
383 struct Qdisc **old)
384{
385 struct tbf_sched_data *q = qdisc_priv(sch);
386
387 if (new == NULL)
388 new = &noop_qdisc;
389
390 sch_tree_lock(sch);
391 *old = q->qdisc;
392 q->qdisc = new;
393 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
394 qdisc_reset(*old);
395 sch_tree_unlock(sch);
396
397 return 0;
398}
399
400static struct Qdisc *tbf_leaf(struct Qdisc *sch, unsigned long arg)
401{
402 struct tbf_sched_data *q = qdisc_priv(sch);
403 return q->qdisc;
404}
405
406static unsigned long tbf_get(struct Qdisc *sch, u32 classid)
407{
408 return 1;
409}
410
411static void tbf_put(struct Qdisc *sch, unsigned long arg)
412{
413}
414
415static void tbf_walk(struct Qdisc *sch, struct qdisc_walker *walker)
416{
417 if (!walker->stop) {
418 if (walker->count >= walker->skip)
419 if (walker->fn(sch, 1, walker) < 0) {
420 walker->stop = 1;
421 return;
422 }
423 walker->count++;
424 }
425}
426
427static const struct Qdisc_class_ops tbf_class_ops = {
428 .graft = tbf_graft,
429 .leaf = tbf_leaf,
430 .get = tbf_get,
431 .put = tbf_put,
432 .walk = tbf_walk,
433 .dump = tbf_dump_class,
434};
435
436static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
437 .next = NULL,
438 .cl_ops = &tbf_class_ops,
439 .id = "tbf",
440 .priv_size = sizeof(struct tbf_sched_data),
441 .enqueue = tbf_enqueue,
442 .dequeue = tbf_dequeue,
443 .peek = qdisc_peek_dequeued,
444 .drop = tbf_drop,
445 .init = tbf_init,
446 .reset = tbf_reset,
447 .destroy = tbf_destroy,
448 .change = tbf_change,
449 .dump = tbf_dump,
450 .owner = THIS_MODULE,
451};
452
453static int __init tbf_module_init(void)
454{
455 return register_qdisc(&tbf_qdisc_ops);
456}
457
458static void __exit tbf_module_exit(void)
459{
460 unregister_qdisc(&tbf_qdisc_ops);
461}
462module_init(tbf_module_init)
463module_exit(tbf_module_exit)
464MODULE_LICENSE("GPL");